1. Field of the Invention
This invention pertains to closures formed of flat material for holding closed the necks of flexible bags and to strips of such closures which can be separated by breaking the connections between adjacent closures on the strip.
2. Description of the Prior Art
The first invention of this application pertains to a flat, generally rigid bag closure of the type having a side edge, bag-neck access opening which joins an enlarged central bag-neck confining aperture. This type of closure is well known, with typical examples being shown in U.S. Pat. Nos. 3,164,250 and 3,822,441, and British Pat. No. 1,409,426. These closures have all included a bag-neck confining aperture, with the shape of the aperture differing from a generally smooth peripheral edge, as in U.S. Pat. No. 3,164,250, to a plurality of sharpened points, as in U.S. Pat. No. 3,822,441, or, as in British Pat. No. 1,409,426, a pair of blunted, inward protrusions. In one other known closure of this type, protrusions of the type shown in the British specification terminate in sharp points for better gripping the bag neck.
The purpose of sharpened points on the protrusions or appendages extending into the bag-neck confining aperture is to grip the neck of the bag to keep it from moving lengthwise of the bag out of the closure and to keep the bag from moving laterally back out through the bag-neck access opening. The location and shape of the protrusions within the bag-neck confining opening, however, are critical. Whereas the smooth type of aperture, such as in U.S. Pat. No. 3,164,250, will hold many bags, it tends to slide on some types of plastic bag materials. On the other hand, the sharp-pointed protrusions in the bag-neck confining opening of the closure in U.S. Pat. No. 3,822,441, while ideally suited for open-mesh net bags, will perforate or tear some types of plastic bag materials. The protrusions in British Pat. No. 1,409,426, and with sharpened ends on the protrusion of the type shown in the British specification, have tended to follow the worst features of both having not a sufficient number of sharpened points for good holding of most plastic bag materials, but where sharpened, having the location of the points in poor locations for good bag holding but tending to cause bag perforation or tearing.
It is thus an object of this invention to provide a flat closure of the type having a side edge bag-access opening to a bag-neck confining aperture in which a plurality of spaced, inwardly extending appendages are provided to better hold plastic-film bag materials without damaging the bag material.
It is another object of this invention to provide a flat closure of the type having a side edge access opening to a bag-neck confining aperture in which there are a plurality of peripherally spaced appendages which separately hold multiple folds of the bag neck material for greater resistance to sliding on the bag neck.
Basically, these objects are achieved by providing a flat, generally rigid closure having a side edge, bag-neck access opening which joins a bag-neck confining aperture, the bag-neck confining aperture having a periphery defined by a plurality of peripherally spaced, inwardly extending appendages, each having a blunted inner edge and at least one bag-gripping sharp corner and wherein the spaces between and around said appendages receive the neck of the bag, with the sharp corners holding the flexible bag against endwise and sidewise movement through the closure. In the preferred embodiment, sharpened jaws define the access opening and three spaced, additional appendages are provided, with the blunted inner edges of the appendages facing towards the center of the aperture and each terminating in opposite pairs of sharpened corners which generally face the corners of adjacent appendages and jaws of the access opening. The multiple sharpened corners hold the flexible, slippery plastic material well regardless of the type of material and amount of material being fed into the bag-neck confining aperture. The blunted edges, however, press more gently against the bag material to reduce penetration or tearing of the bag material by the sharpened corners. In the preferred embodiment, the appendages and jaws of the access opening provide eight different points of bag gripping while allowing the bag to wrap itself into the spaces around and between the points for better gripping of the bag neck material. It is particularly advantageous to have one of the appendages directly aligned with the bag-access side opening and with its blunted edge facing the opening so that bag neck material being fed in through the bag-access opening will not snag on the appendage, allowing the material to be fed completely into the aperture and reducing the chance of tearing the bag material as it is fed or pushed in through the access opening.
A second invention of this application is a web-attachment technique for adjacent closures in a multi-closure strip of closures, each of the type having a side edge, bag-neck access opening joining a bag-neck confining aperture. Multi-strip closures of this type are shown, for example, in U.S. Pat. No. 3,164,250, which are joined side-by-side, or in U.S. Pat. No. 3,164,249, which are joined end-for-end, and these closures have webs or strips of attachment between adjacent closures in the strip which are spaced transversely of the length of the strip and are of a sufficient thickness lengthwise of the strip to space the adjacent closures along the strip. When the closure is placed on a bag neck, the webs at spaced fracture points are broken to separate the closure from the strip. In some cases, the fracture point does not sever cleanly at the edge of the closure, leaving a jagged protruding tab. These jagged tabs can be an annoyance as they give a rough feel to the otherwise smooth edge of the closure or can snag the plastic bag material of other bags when packed together. Various attempts by others have been made to reduce the formation of rough tabs, an example being shown in British Pat. No. 1,409,426, mentioned above. These other attempts have generally been unsatisfactory.
It is an object of this invention, therefore, to provide attachments between closures in a multi-closure strip which are shielded when the fracture points are broken during the removal of a strip so that the fracture points do not protrude from the edge of the separated closure as thin jagged tabs.
It is another object of this invention to provide transversely spaced points of attachment between adjacent closures in a multi-closure strip which are each provided with a blunted shielding surface adjacent the point of attachment with the next adjacent closure.
Basically, these objects are obtained by providing a multi-closure strip of the type in which each closure has a side bag-neck access opening which joins a bag-neck confining aperture with transversely spaced webs or points of fracture between the adjacent closures in the strip and which separate the closures lengthwise along the strip. The webs are provided with enlarged bases which terminate at the point of fracture so that upon removal of a closure from the strip, the enlarged base shields the point of fracture, reducing the chance of snagging on bag material or of leaving a jagged feel to the edge of the closure. In the preferred embodiment of the invention, each closure is provided with webs on each side or edge of the closure lengthwise of the strip, with each web having an enlarged base. Preferably, the enlarged bases are generally convex in relation to the length of the strip. In alternative embodiments, however, the closures can be provided with webs only on one edge lengthwise of the strip, with the point of fracture being flush with the adjacent joined edge of the next adjacent closure. Also, in alternative embodiments, the enlarged base can have its most lateral edge of each web rounded or blunted to shield the point of fracture, but its inner edge can be left generally straight, with some loss of protection to the point of attachment. As it is well understood, the closures can be joined end-for-end or side-by-side, as shown in U.S. Pat. Nos. 3,164,250 and 3,164,249, with the principles of this invention applying to either arrangement.
The third invention of this application is a light-weight plastic bag closure of the type having a flat body with a bag-neck side access opening which joins with a bag-neck confining aperture within the body, the improvement providing a plurality of closed openings surrounded by a pattern of solid webs. The closed openings are provided to reduce the amount of plastic used in the manufacture of the closure, with the pattern of solid webs provided to maintain a high degree of strength in areas in which twisting or severe stress loading occurs on the closure. Prices of raw plastic material for the manufacture of closures has more than tripled in the past few years, making it desirable to reduce the amount of plastic used in the manufacture of a closure. By providing the closure with a series of closed openings arranged in a pattern which leaves solid webs at the high stress areas, the removed plastic can be recycled, greatly reducing the cost of the closures without weakening the closures.
These objects and advantages are obtained in this invention by providing the plastic bag closure of the type having a flat, generally rigid body and a side bag-neck access opening communicating with a bag-neck confining aperture, with a plurality of closed openings surrounding the aperture and separated by a pair of first solid webs which lie generally perpendicular to a line through the side bag-neck access opening and adjacent opposite sides of said bag-neck confining aperture, and a peripheral solid web around the closed openings starting at one side of the bag-access opening and continuing around between the periphery of the closure outside of the closed openings to the other side of the bag-access opening. In the preferred embodiment, additional closed openings and webs are provided, with a second solid web positioned in alignment with the bag-access opening between the peripheral web and the aperture and with third solid webs located along generally parallel lines on opposite sides of the aperture and generally parallel to a line through the bag-neck access opening.